The No. 1 reason the Fed shouldn’t raise interest rates? The economy may already be slowing, and may be a lot weaker than the Fed and others think. The best evidence of that came from last month’s jobs report.

On the surface, the jobs report for August looked pretty good. The unemployment rate dropped to 5.1%, and employers added 173,000 new workers to their payrolls, which was less than expected but in the right direction. The problem: job growth is coming from the wrong places.

Thomas Lam, an economist at RHB Securities in Singapore, separated out the 173,000 new August jobs into cyclical and non-cyclical industries. What Lam found was that “employment growth in the cyclically-sensitive private industries, which tends to lead hiring in other sectors over time, seems to be trending lower.” The three-month average job growth from cyclical sectors is around 30,000. Last month, according to Lam’s analysis, it was pretty close to zero.

In August, just 3,000 new jobs came from construction. Trucking companies added just 700 workers to their payrolls. The manufacturing sector lost 17,000 jobs. Healthcare, on the other hand, added more than 40,000 jobs. More jobs in healthcare is not typically associated with a stronger economy. The government added 33,000 jobs.

Of course, some argue that a slowing economy, or the prospect of one, makes an even stronger case for the Fed to raise interest rates now. The Fed will need higher interest rates to speed the economy up again. This logic, though, is perverse. The Fed does raise and lower interest rates over time, but these actions tend to take place over long cycles. The Fed should avoid a quick round trip, and the damage that will cause. Plus, Europe has shown that interest rates can go below zero.

The Fed does have a history of overestimating the strength of the economy. Now would be a really, really bad time to do that.